urllib3 PoolManger issue on pypy3 tests

[shalevr]

There is an issue with the new urllib3 version(1.26.16) on pypy3, the test_basic_http_success_using_connection_pool test doesn't finish.

According to the urllib3 documentation the new version fixed:

Fixed thread-safety issue where accessing a PoolManager with many distinct origins
would cause connection pools to be closed while requests are in progress (#2954 <https://github.com/urllib3/urllib3/pull/2954>_)

It might be related to the HttpTestbase and to the HTTPServer thread.

[shalevr]

In the meantime, I opened PR that skipped the urlib3 tests on pypy3
#1826

[srikanthccv]

Yeah, I think this is an issue with how we test because both urllib3 and requests have pypy tests as part of their CI workflows, so if it works there, it should pass here.

[shalevr]

Yeah, I think this is an issue with how we test because both urllib3 and requests have pypy tests as part of their CI workflows, so if it works there, it should pass here.

Exactly, it's probably the HttpTestBase class that both urllib3 and requests inherit from it.